/*
 * Copyright (C) 2012 The Guava Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.common.io;

import com.google.common.base.Charsets;
import com.google.common.base.Optional;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Lists;
import com.google.common.io.SourceSinkFactory.ByteSourceFactory;
import com.google.common.io.SourceSinkFactory.CharSourceFactory;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.Reader;
import java.io.StringWriter;
import java.lang.reflect.Method;
import java.util.List;
import java.util.Map.Entry;

import junit.framework.TestSuite;

/**
 * A generator of {@code TestSuite} instances for testing {@code CharSource} implementations.
 * Generates tests of a all methods on a {@code CharSource} given various inputs the source is
 * expected to contain.
 *
 * @author Colin Decker
 */
@AndroidIncompatible // Android doesn't understand tests that lack default constructors.
public class CharSourceTester extends SourceSinkTester<CharSource, String, CharSourceFactory>
{

    private static final ImmutableList<Method> testMethods = getTestMethods(CharSourceTester.class);

    static TestSuite tests(String name, CharSourceFactory factory, boolean testAsByteSource)
    {
        TestSuite suite = new TestSuite(name);
        for (Entry<String, String> entry : TEST_STRINGS.entrySet())
        {
            if (testAsByteSource)
            {
                suite.addTest(
                        suiteForBytes(
                                factory, entry.getValue().getBytes(Charsets.UTF_8), name, entry.getKey(), true));
            }
            else
            {
                suite.addTest(suiteForString(factory, entry.getValue(), name, entry.getKey()));
            }
        }
        return suite;
    }

    static TestSuite suiteForBytes(
            CharSourceFactory factory, byte[] bytes, String name, String desc, boolean slice)
    {
        TestSuite suite = suiteForString(factory, new String(bytes, Charsets.UTF_8), name, desc);
        ByteSourceFactory byteSourceFactory = SourceSinkFactories.asByteSourceFactory(factory);
        suite.addTest(
                ByteSourceTester.suiteForBytes(
                        byteSourceFactory, bytes, name + ".asByteSource[Charset]", desc, slice));
        return suite;
    }

    static TestSuite suiteForString(
            CharSourceFactory factory, String string, String name, String desc)
    {
        TestSuite suite = new TestSuite(name + " [" + desc + "]");
        for (Method method : testMethods)
        {
            suite.addTest(new CharSourceTester(factory, string, name, desc, method));
        }
        return suite;
    }

    private final ImmutableList<String> expectedLines;

    private CharSource source;

    public CharSourceTester(
            CharSourceFactory factory, String string, String suiteName, String caseDesc, Method method)
    {
        super(factory, string, suiteName, caseDesc, method);
        this.expectedLines = getLines(expected);
    }

    @Override
    protected void setUp() throws Exception
    {
        this.source = factory.createSource(data);
    }

    public void testOpenStream() throws IOException
    {
        Reader reader = source.openStream();

        StringWriter writer = new StringWriter();
        char[] buf = new char[64];
        int read;
        while ((read = reader.read(buf)) != -1)
        {
            writer.write(buf, 0, read);
        }
        reader.close();
        writer.close();

        assertExpectedString(writer.toString());
    }

    public void testOpenBufferedStream() throws IOException
    {
        BufferedReader reader = source.openBufferedStream();

        StringWriter writer = new StringWriter();
        char[] buf = new char[64];
        int read;
        while ((read = reader.read(buf)) != -1)
        {
            writer.write(buf, 0, read);
        }
        reader.close();
        writer.close();

        assertExpectedString(writer.toString());
    }

    public void testCopyTo_appendable() throws IOException
    {
        StringBuilder builder = new StringBuilder();

        assertEquals(expected.length(), source.copyTo(builder));

        assertExpectedString(builder.toString());
    }

    public void testCopyTo_charSink() throws IOException
    {
        TestCharSink sink = new TestCharSink();

        assertEquals(expected.length(), source.copyTo(sink));

        assertExpectedString(sink.getString());
    }

    public void testRead_toString() throws IOException
    {
        String string = source.read();
        assertExpectedString(string);
    }

    public void testReadFirstLine() throws IOException
    {
        if (expectedLines.isEmpty())
        {
            assertNull(source.readFirstLine());
        }
        else
        {
            assertEquals(expectedLines.get(0), source.readFirstLine());
        }
    }

    public void testReadLines_toList() throws IOException
    {
        assertExpectedLines(source.readLines());
    }

    public void testIsEmpty() throws IOException
    {
        assertEquals(expected.isEmpty(), source.isEmpty());
    }

    public void testLength() throws IOException
    {
        assertEquals(expected.length(), source.length());
    }

    public void testLengthIfKnown() throws IOException
    {
        Optional<Long> lengthIfKnown = source.lengthIfKnown();
        if (lengthIfKnown.isPresent())
        {
            assertEquals(expected.length(), (long) lengthIfKnown.get());
        }
    }

    public void testReadLines_withProcessor() throws IOException
    {
        List<String> list =
                source.readLines(
                        new LineProcessor<List<String>>()
                        {
                            List<String> list = Lists.newArrayList();

                            @Override
                            public boolean processLine(String line) throws IOException
                            {
                                list.add(line);
                                return true;
                            }

                            @Override
                            public List<String> getResult()
                            {
                                return list;
                            }
                        });

        assertExpectedLines(list);
    }

    public void testReadLines_withProcessor_stopsOnFalse() throws IOException
    {
        List<String> list =
                source.readLines(
                        new LineProcessor<List<String>>()
                        {
                            List<String> list = Lists.newArrayList();

                            @Override
                            public boolean processLine(String line) throws IOException
                            {
                                list.add(line);
                                return false;
                            }

                            @Override
                            public List<String> getResult()
                            {
                                return list;
                            }
                        });

        if (expectedLines.isEmpty())
        {
            assertTrue(list.isEmpty());
        }
        else
        {
            assertEquals(expectedLines.subList(0, 1), list);
        }
    }

    private void assertExpectedString(String string)
    {
        assertEquals(expected, string);
    }

    private void assertExpectedLines(List<String> list)
    {
        assertEquals(expectedLines, list);
    }
}
